Image formation apparatus with cartridge for roll of photosensitive sheet

ABSTRACT

A cartridge containing a roll of photosensitive sheet and set inside an image formation apparatus has both an outlet and an inlet. Its interior is divided by a flexible sheet into a chamber originally containing the roll of unused photosensitive sheet and another chamber into which used portion of the sheet is collected through the inlet. A roller near the outlet for contacting the photosensitive sheet to thereby pull it out of the cartridge operates only for a specified length of time or until a specified length of an uncoated leading section of the photosensitive sheet is pulled out and thereafter the roller is removed from the contacting position with the photosensitive sheet so as not to contact and damage the microcapsule-coated part of the photosensitive sheet which follows the leading section.

BACKGROUND OF THE INVENTION

This invention relates to an image formation apparatus with a cartridgefor housing a roll of photosensitive sheet.

Of particular interest for application of this invention arephotosensitive sheets of the type disclosed, for example, in JapanesePatent Publication Tokkai No. 58-88739 comprised of a flexible basesheet coated with microcapsules encapsulating a colorless dye and aphotopolymerizing agent which hardens by exposure to light. When aphotosensitive sheet like this is exposed to an image forming beam oflight such as reflected light from an original document to be copied,those of the microcapsules exposed to light harden while those notexposed remain soft such that an invisible image, or a pattern, ofselectively hardened microcapsules is formed on the sheet. A visibleimage can be obtained from such an invisible image by superposinglycovering the invisible pattern with an image transfer sheet coated witha developer material and pressing them together such that only those ofthe microcapsules which are not hardened by exposure to light areruptured, causing the encapsulated colorless dye to flow out. Thedeveloper material is so selected as to have a chromogenic effect on thedye encapsulated in the microcapsules. Thus, the dye flowing out of theruptured microcapsules becomes visible, producing a visible image on thetransfer sheet.

In an image formation process of this type, it is important to protectthe surface of the photosensitive sheet coated with microcapsules notonly against external light but also against external force before it isexposed to the image forming beam of light because an external force mayrupture the microcapsules. One method of achieving this is to preparethe photosensitive sheet in the form of a roll and set it inside thehousing structure of the image formation apparatus. An additionaladvantage of preparing the photosensitive sheet in a rolled form is thatit can then be directly wound around a cylindrical drum on the surfaceof which an exposure point is defined by an optical system. In thismanner, the photosensitive sheet can be supplied and transported by therotation of this drum and feeding rollers and the like for transportingcut sheets from a cassette can be dispensed with. In other words, thecoated surface of the photosensitive sheet can be protected againstfrictional force of these rollers. If the sheet is rolled up and setinside the housing structure, furthermore, it can also be safelyprotected against exposure to external light.

A rolled photosensitive sheet, however, risks the danger of exposure tolight before it is set inside the housing structure of the imageformation apparatus. Moreover, a roll of photosensitive sheet to bedirectly set inside the image formation apparatus is not easy to workwith. Thus, there have been ideas of providing a detachably attachablecartridge inside an image formation apparatus for supporting such a rollof photosensitive sheet. A trouble with such an idea is that thecartridge must be so structured that a front edge of the rolled sheetstored inside can be easily pulled outside. When such a cartridge is setinside an image formation apparatus, the user must pull out the frontedge of the sheet somehow and wrap it around the drum, etc. This, too,is a cumbersome job.

With a cartridge of a simple type intended only for an unused roll ofphotosensitive sheet, furthermore, there must be provided an additionalspace somewhere inside the housing structure of the image formationapparatus for storing the used part of the sheet. If the photosensitivesheet comprises a film of 25 μm in thickness and is capable of copying1000 images of size A4 in its longitudinal direction, the externaldiameter of its roll becomes about 120 mm. Not only is a cartridgelarger than this size necessary but an extra space of comparable sizemust also be provided inside the housing structure for the used sheet.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide an imageformation apparatus with a cartridge for storing therein a roll ofphotosensitive sheet from which the front edge of the sheet storedtherein can be automatically pulled out after the cartridge is setinside the housing structure of the image formation apparatus.

It is another object of the present invention to provide an imageformation apparatus as described above which does not require a largeadditional space for storing used part of the photosensitive sheet.

It is a further object of the present invention to provide an imageformation apparatus with a cartridge as described above which does notdamage the coated surface of the photosensitive sheet as it is pulledout.

The above and other objects of the present invention are achieved byproviding a cartridge having both an outlet and an inlet formed on itshousing for the photosensitive sheet contained therein to pass throughto go out and to be led in, respectively. The interior of the cartridgeis separated by a flexible screen into a chamber containing the roll ofphotosensitive sheet initially and another chamber into which usedportion is collected. In the beginning, a relatively stiff leadingsection at the front end of the photosensitive sheet is at the outlet. Adelivery roller disposed near the outlet is then contacted to thisleading section and pulls the photosensitive sheet out of the cartridge.After a predetermined length of the leading section of thephotosensitive sheet has been pulled out or after the delivery roller isoperated for a predetermined length of time, the delivery roller isremoved from the surface of the photosensitive sheet so as not tocontact the microcapsule-coated part of the photosensitive sheet. Themotion of the photosensitive sheet is thereafter controlled by a maindrum and a roller for applying pressure on its surface.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part ofthe specification, illustrate an embodiment of the present inventionand, together with the description, serve to explain the principles ofthe invention. In the drawings:

FIG. 1 is a schematic front sectional view of an image formationapparatus embodying the present invention to show its internalstructure,

FIG. 2 is a schematic front sectional view of the image formationapparatus of FIG. 1 when its upper unit is open,

FIG. 3 schematic front sectional view of the image formation apparatusof claim 1 when its upper unit is open before the cartridge is set,

FIG. 4 a sectional front view of a cartridge embodying the presentinvention,

FIG. 5 is a sectional front view of the cartridge of FIG. 4 when thephotosensitive sheet therein is nearly completely used up,

FIG. 6 is a diagonal view of a mechanism for controlling the deliveryroller,

FIG. 7 is a block diagram of a control unit for the image formationapparatus of FIG. 1,

FIG. 8 is a flow chart for the operation of the CPU of FIG. 7 when thecartridge is set,

FIG. 9 is a drawing for showing the positional relationships of pointson the leader section of the photosensitive sheet,

FIG. 10 is a schematic sectional front view of another cartridgeembodying the present invention, and

FIG. 11 is a diagonal view of the cartridge of FIG. 10.

In all these figures, identical or equivalent components are indicatedby the same numerals.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows the structure of an image formation apparatus embodying thepresent invention adapted to use a photosensitive sheet of the kindcomprising a base sheet coated with microcapsules encapsulating acolorless dye and a photopolymerizing monomar. A document table 2 isprovided at the top of a housing structure 1 and an original document 3to be copied placed on top of the document table 2 is scanned by anoptical system 4 of a known kind comprised of two source lamps 40 and41, reflective mirrors 42-45 and a lens 46. At the lower right-hand partof the housing structure 1 is a paper cassette 5 containing imagetransfer sheets 6. A feeder roller 7 serves to transport the transfersheets 6 one sheet at a time to compression section through guidingrollers 8.

Nearly at the center of the housing structure 1 is a main drum 9 whichserves as the upper one of a pair of compression rollers. Below the maindrum 9 and opposite thereto is a pressure applying roller 10 whichserves as the lower one of the pair of compression rollers. A cartridge9 embodying the present invention containing therein a roll ofphotosensitive sheet 13 is detachably attached to the housing structure1 somewhat above and to the left of the main drum 9. During operation ofthe image formation apparatus, the photosensitive sheet supplied fromthe cartridge 11 is wound half-way around the main drum 9. A point onthe upper right-hand side of the surface of the main drum 9 indicated byPl is an exposure point where image forming light reflected from thedocument 3 is directed and focused by the optical system 4. The point atwhich the main drum 9 and the pressure applying roller 10 contact eachother is defined as the pressure point P2 where the photosensitive sheet13 and one of the transfer sheets 6 are superposed one on top of theother and sandwiched together between the main drum 9 and the pressureapplying roller 10. A blade 15 is disposed on the left-hand side of thepressure point P2 and serves to separate the photosensitive sheet 13 andthe transfer sheet 6 after they pass through the pressure point P2,sending the transfer sheet 6 alone downward.

To the left of the blade 15 is a conveyor belt 17. To the left of theconveyor belt 17 are heat rollers 18, discharge rollers 19 and adischarge tray 20 in this order. The transfer sheet 6 separated by theblade 15 is transported by the conveyor belt 17 to the left and broughtto the heat rollers 18 which serve to give luster to the visible imageformed on the transfer sheet 6. The transfer sheet 6 is coated not onlywith a developer material but also with a thermoplastic resin whichmelts by the heat of the heat rollers 18 as the image carrying transfersheet 6 passes therethrough and makes a uniform surface over the image.This technology has already been disclosed, for example, in JapanesePatent Publication Tokkai No. 60-259490. After passing through the heatrollers 18, the transfer sheet 6 is discharged onto the discharge tray20 by the discharge rollers 19.

In the meantime, the photosensitive sheet, after passing the pressurepoint P2, passes between cartridge inlet rollers 12 and is dischargedinto the cartridge 11. As will be described more fully below, theinterior of the cartridge 11 is divided by a light-screening flexiblepartition 11a into an upper chamber Rl for containing an unused sheetand a lower chamber R2 for storing used parts of the photosensitivesheet. The cartridge 11 is provided with an outlet 11c on its upperright-hand side and an inlet 11d on its lower right-hand side. At theoutlet 11c is a roller 11b partially exposed to the exterior of itshousing to serve as the lower one of a pair of delivery rollers. Anotherroller 30 which serves as the upper one of the delivery rollers isdisposed opposite to the lower delivery roller 11b and rotatablysupported by arms 31 (only the front one visible in FIG. 1) which, inturn, are rotatably supported by the housing structure 1 so as to bemovable as indicated by a double-headed arrow. The upper delivery roller30 is in motion-communicating relationship with a power source in thehousing structure 1 such that, when it is in the position shown bybroken lines in FIG. 1, the photosensitive sheet 13 is sandwichedbetween the delivery rollers 30 and 11b and is delivered in thedirection of a double arrow by the rotation thereof. As will beexplained more fully below, the upper delivery roller 30 assumes theposition of the broken lines only during a specified period of timeafter the cartridge 11 is set to the housing structure 1 of the imageformation apparatus such that only the front end part of thephotosensitive sheet not coated with microcapsules is pulled out from aroll 14 through the outlet 11c by a specified distance determined by thelength of the uncoated leader section. The front end is thereafterwrapped around the main drum 9, passed between the cartridge inletrollers 12 and directed into the lower chamber R2 of the cartridge 11through its inlet 11d. After the front end of the photosensitive sheet13 is pulled out of the outlet 11c by the aforementioned specifieddistance, the upper delivery roller 30 is lifted to the position shownby solid lines in FIG. 1 so as not to contact the microcapsule-coatedsurface of the photosensitive sheet to apply any pressure thereon.

The housing structure 1 consists basically of an upper unit A and alower unit B such that the upper unit A can be opened and closedrotatably with respect to the lower unit B around a pin 27. The upperunit A contains the main drum 9 and the cartridge 11 while the lowerunit B contains the pressure applying roller 10 and the components fortransporting the image transfer sheets 6. When it is desired to set thecartridge 11 into the housing structure 1, the upper unit A is opened asshown in FIG. 2 with respect to the lower unit B and a front panel (notshown) is opened. FIG. 3 shows the interior of the housing structure 1before the cartridge 11 is set. As shown, an axis 22 is attached to theupper unit A perpendicularly to the page and there is also provided acartridge detector sensor 21 for detecting whether the cartridge 11 hasbeen set properly. A positioning protrusion 24 is also formed on theupper unit A above and to the left of the axis 22. In order to set thecartridge 11 to the upper unit A, a tubular shaft (to be described morefully below) at the center of the row 11 is allowed to be penetrated bythe axis 22 and the top left-hand edge of the cartridge housing ismatched against the positioning protrusion 24. The cartridge detectorsensor 21 is switched on only if the cartridge 11 is properly set to theupper unit A and the control unit (to be described more fully below) ofthe image formation apparatus starts to rotate the delivery rollers 30and 11b only upon learning that the cartridge 11 has been properly setby receiving a signal from the sensor 21. Another sensor 23 fordetecting whether the upper unit A is open with respect to the lowerunit B is disposed at the lower right-hand end of the upper unit A. Astill another sensor 26 is provided immediately behind the cartridgeinlet rollers 12 for detecting the position of the incomingphotosensitive sheet 13.

The main drum 9 is started when a start switch on a control panel (notshown) is operated after the photosensitive sheet 13 is already wrappedtherearound. Rotation of the main drum 9 causes the photosensitive sheet13 to be pulled out of the cartridge 11, exposed to the image forminglight from the document 3 at the exposure point Pl and brought to thepressure point P2. At the exposure point Pl, the photopolymerizingmonomer inside those of the microcapsules exposed to light correspondingto a white area of the document 3 undergoes a polymerization reaction,hardening these exposed capsules selectively. The capsules at positionscorresponding to black areas of the document 3 remaining soft, aninvisible image, or a pattern, is thereby formed on the photosensitivesheet 13. At the pressure point P2, the photosensitive sheet 13 carryingthis invisible image is pressed together with the transfer sheet 6 and avisible image is transferred onto the transfer image 6 by chromogenicreaction of the dye flowing out of ruptured microcapsules as describedabove and known by persons skilled in the art.

After the image is thus transferred, the photosensitive sheet 13 isdischarged through the cartridge inlet rollers 12 back into thecartridge 11 while the transfer sheet 6 now carrying a visible imagethereon is separated from the photosensitive sheet 13 by the blade 15and is transported to the heat rollers 18 by which a lustrous surface isformed thereon before the transfer sheet 6 is discharged onto thedischarge tray 20.

The cartridge 11 is structured, as shown more in detail in FIG. 4, witha tubular shaft 25 carrying a roll 14 of photosensitive sheet 13 insideits housing 11e, the lower delivery roller 11b and the light-screeningflexible partition 11a which divides the interior of the cartridge 11into upper and lower chambers Rl and R2 as briefly described above. Theinlet 11d into the lower chamber R2 is provided with shutters 11f fromabove and below. The partition 11a may be a black polyethylene or papersheet and is affixed at both ends to inner walls of the cartridge 11 bymeans of fixing pieces 11h so as to envelope the lower half of the sheetroll 14.

A protrusion 13a is formed at the front edge of the photosensitive sheet13 unwound from the roll 14. A front end portion of the photosensitivesheet 13 with a specified length L from this protrusion 13a is made of arelatively stiff material and is not coated with microcapsules. Thisportion is what was referred above as the leader section. Before thecartridge 11 is set to the housing structure 1, the protrusion 13a atthe front edge of the photosensitive sheet is exactly at the position ofthe delivery roller 11b with the leader section in contact with theupper surface of this delivery roller 11b. Since the leader section isrelatively stiff, it does not sag but maintains a straight position asshown in FIG. 4. The lower delivery roller 11b is partially exposed tothe exterior through the opening 11c formed in the housing 11e and theprotrusion 13a at the front edge of the leader section of thephotosensitive sheet 13 is also exposed through this opening 11c to theexterior opposite to the upper delivery roller 30.

The lower chamber R2 of the cartridge 11 serves to store the usedportion of the photosensitive sheet 13 brought in through the inlet 11d.The two shutters 11f at this inlet 11d are rotatably supported by axes11g such that the photosensitive sheet 13, once brought inside, does notgo outside again through the same inlet 11d. FIG. 5 shows the conditionof the interior of the cartridge 11 when the roll 14 of photosensitive13 is nearly completely used up and a major portion thereof is alreadyinside the lower chamber R2 of the cartridge 11. In a situation likethis, the lower chamber R2 must be large enough to accommodate a largebulk of the photosensitive sheet 13 but since the partition 11aseparating the upper and lower chambers Rl and R2 is flexible and islong enough to initially sag at the center, it is automatically pushedupward as the lower chamber R2 is filled up. In the meantime, since thevolume required for the upper chamber R1 keeps diminishing as the roll14 is used up, the partition 11a is not prevented from being pushedupward. In summary, the cartridge 11 according to the present inventionis characterized as having a flexible partition sheet inside to separatethe two chambers formed therein such that the space inside the cartridge11 can be effectively used both for protecting a roll of unusedsensitive sheet and for storing used portions thereof. In other words,there is no need to reserve a large space separately for storing usedsheet and the housing structure is allowed to be compactly designed.

When the upper unit A is opened as shown in FIG. 2, the cartridge 11becomes tilted and this has the favorable effect of pushing usedportions of photosensitive sheet to the deeper (left-hand) end of thelower chamber R2 by gravity. Thus, portions of used photosensitive sheetjust brought into the lower chamber R2 are moved deeper inside the lowerchamber R2 and the space therein can be more effectively utilized foraccepting later-coming used portions. FIG. 5 shows the used portionsnearly uniformly distributed inside the lower chamber R2 after the upperunit A is opened and closed many times. When the upper unit A is openedas shown in FIG. 3, furthermore, the pressure applying roller 10 becomesautomatically separated from the main drum 9, thereby allowing the userto remove a jammed sheet at the pressure point P2, if there is a jam.

The upper delivery roller 30, which was only sketchily described above,and its mechanism for operation are explained next more fully withreference to FIG. 6. The upper delivery roller 30 is approximately ofthe same length as the width of the photosensitive sheet 13 and isaffixed to an axis 32 attached to end parts of the arms 31 which arerotatably supported by another axis 33. A gear 34 engaged with a drivinggear 35 provided to the housing structure 1 of the image formationapparatus is attached to one end of this axis 33. Actuators of solenoids36 are attached to the distal ends of the arms 31 away from the roller30. Rollers 37 and 38 are respectively fastened to the axes 33 and 32,and endless belts 39 are stretched therebetween. The ends of the arms 31where the delivery roller 30 is attached are upwardly raised by springs50.

With a mechanism thus assembled as shown in FIG. 6, the delivery roller30 is normally lifted as shown by solid lines in FIG. 1 because of thesprings 50. When the solenoids 36 are switched on, however, the arms 31are rotated in the clockwise direction until the roller 30 assumes theposition indicated by broken lines in FIG. 1 and contacts the lowerconveyor roller 11b if the cartridge 11 is set. Thus, if thephotosensitive sheet 13 is already sandwiched therebetween, it can bepulled out of the cartridge 11 automatically. The roller 30 is moved bycommunicating the motion of the gear 34 through the belts 39. As will beexplained more fully below, the motion of the roller 30 for pulling outthe photosensitive sheet 13 is started after both the cartridge detectorsensor 21 and the upper-unit detector sensor 23 are switched on andstopped when the sheet sensor 26 detects the front edge of thephotosensitive sheet 13 (or by waiting a specified length of timethereafter) as the solenoids 36 are switched off.

The image formation apparatus described above is controlled as shown inthe block diagram of its control unit by a central processing unit CPU60 which is connected to a read-only memory ROM 61, a random-accessmemory RAM 62 and input/output interface circuits 63 and 64. The I/0interface 63 is connected to a driver 65 for the solenoids 36, a driver66 for the main drum 9, a control unit 67 for the transportation oftransfer sheets 6, a control unit 68 for the optical system 4 and acontrol unit 69 for the heat rollers 18, fans and the like. The I/0interface 64 is connected to detector sensors 70 including theaforementioned cartridge detector sensor 21, upper-unit detector sensor23 and sheet sensor 26, and a control panel 71 inclusive of a key-inputsection 71a and a display device 71b.

Operation by the CPU 60 when the cartridge 11 is set is explained nextwith reference to the flow chart of FIG. 8 which starts when the frontpanel of the image formation apparatus is opened and the upper unit A islifted. If the cartridge detector sensor 21 is on (YES in n1), thismeans either that a new cartridge has been set or that an old cartridgeis still available. In either situation, the condition of thephotosensitive sheet 13 as reported by the sheet sensor 26 is examinednext (n2). If the sheet sensor 26 is off, this means that a newcartridge 11 has just been set. If the sheet sensor 26 is on, the imageformation apparatus is ready to be used and there is nothing required tobe done. If the cartridge 11 now set is a new one, the control unitwaits until the upper unit A is closed and this is detected by theupper-unit detector sensor 23 (YES in n3). Alternatively, the sensor 23maybe designed to be switched on when both the upper unit A and thefront panel of the image formation apparatus are closed. Alternativelystill, closing of the front panel need not be made a condition foradvancing to Step n4.

After a few seconds (n4), a timer t₁ assigned to the RAM 62 is reset(n5), the solenoids 36 are switched on and the delivery roller 30, themain drum 9, the pressure applying roller 10 and the cartridge inletrollers 12 are operated (n6). This causes the leader section of thephotosensitive sheet 13 to be pulled out of the cartridge 11, passesover the surface of the main drum 9 and through the pressure point P2and brought to the exit of the cartridge inlet roller 12 so as to switchon the sheet sensor 26 (n7). When the sheet sensor 26 is switched on, asecond timer t₂ also assigned to the RAM 62 is reset, the solenoids 36are switched off and the delivery roller 30 are stopped (n10). After thesecond timer t₂ counts up a predetermined length of time T₂ (n11),operations of the main drum 9, the pressure applying roller 10 and thecartridge inlet rollers 12 are stopped (n12).

The aforementioned time interval T₂ is determined as follows. As shownin FIG. 9, which illustrates positional relationships among pointstraveled through by the photosensitive sheet 13, the total length L ofthe relatively stiff leader section at the front of the photosensitivesheet 13 is made somewhat (by an extra length of L₁ =1-3 cm) longer thanthe distance between the position of the sheet sensor 26 and that of thedelivery roller 30. Thus, the photosensitive sheet 13 must travel atleast a distance of (L₁ +L₂) after the protrusion 13a at its front endis detected by the sheet sensor 26 such that a microcapsule-coated partof the photosensitive sheet 13 is sure to be at the exposure point Pl,where L₂ represents the distance between the position of the deliveryroller 30 and the exposure point Pl. Thus, if V is the speed of thephotosensitive sheet 13 at which it is advanced, the time interval T₂should be determined by (L₁ +L₂)/V.

With reference again to the flow chart of FIG. 8, if the sheet sensor 26is not switched on (NO in n7) after an elapse of a preset time period T₁which should be sufficient for the front edge of the photosensitivesheet 13 to reach the position of the sheet sensor 26 (YES in n8), thisindicates that the photosensitive sheet 13 is somehow not being pulledout of the cartridge 11. Thus all operations of the solenoids 26, thedelivery roller 30, the main drum 9, the pressure applying roller 10 andthe cartridge inlet rollers 12 are stopped (n13) and after the upperunit A is opened (YES in n14), operations from Step n3 are repeated.

In summary, after a new cartridge 11 is set, the delivery roller 30cooperates with another roller 11b inside the cartridge 11 toautomatically pull out the relatively stiff leader section at the frontend of the photosensitive sheet 13 until its front edge comes to theposition of the cartridge inlet rollers 12. The delivery roller 30 isthen lifted so as not to apply any pressure on the microcapsules withwhich the following part of the photosensitive sheet 13 is coated. Thephotosensitive sheet 13 is thereafter advanced by the rotation of themain drum 9, the pressure applying roller 10 and the cartridge inletrollers 12 until the microcapsule-coated part reaches the exposure pointPl. During an image formation process, the photosensitive sheet 13 islikewise advanced by the main drum 9 and the pressure applying roller10, and since its surface does not contact any roller until it reachesthe pressure point P2, the microcapsules thereon are well protected.Since the back end of the photosensitive sheet 13 is merely lightlyattached to the shaft 25 and can be easily removed therefrom, thephotosensitive sheet 13 can be used effectively without any waste. Whenthe photosensitive sheet 13 is used up, it is completely stored insidethe lower chamber R2 of the cartridge 11 and no part thereof remainsoutside when the cartridge 11 is taken out of the housing structure 1.Thus, there is no danger of leakage of residual dye.

The foregoing description of a preferred embodiment of the invention hasbeen presented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed, and many modifications and variations are possible in lightof the above teaching. With reference to the flow chart of FIG. 8, forexample, the rotation of the delivery roller 30 need not be stopped by asignal from the sheet sensor 26. Instead, the delivery roller 30 may beprogrammed to stop after a predetermined time period estimated to besufficient for the front edge of the photosensitive sheet 13 to reachthe position of the sheet sensor 26.

Structurally, the cartridge inlet rollers 12 need not be disposedoutside the cartridge housing 11e. FIGS. 10 and 11 show anothercartridge embodying the present invention characterized as having a pairof inlet rollers 12 inside its inlet opening 11d with a gear 12aattached to the upper one thereof disposed outside the housing 11e. Adriver gear 27 is supported by the housing structure 1 of the imageformation apparatus so as to engage with this eternally positioned gear12a when the cartridge 1 is set. The lower one of the inlet rollers 12is pressed upward by a plate spring 12b. Since this pair of inletrollers 12 nearly completely cover the inlet 11d and since they canrotate only in the directions of the arrows shown thereon, thephotosensitive sheet 13, once inside, is more strictly prevented fromcoming out of the lower chamber R2.

If the cartridge 11 shown in FIGS. 1-4 is replaced by the one shown inFIGS. 10 and 11, the timing schedule illustrated by way of the flowchart of FIG. 8 may be modified appropriately but such modifications andvariations are apparent to a person skilled in the art and are intendedto be included within the scope of this invention.

What is claimed is:
 1. An image formation apparatus comprisingacartridge having an outlet and containing a rolled photosensitive sheet,a roller disposed near said outlet for contacting said photosensitivesheet to thereby pull said photosensitive sheet out of said cartridge, asensor for outputting a detection signal when said cartridge is detectedas being set in said image formation apparatus, and driving means fordriving said roller in response to said detection signal until apredefined condition comes to be satisfied.
 2. The apparatus of claim 1wherein said driving means drives said roller in response to saiddetection signal for a predetermined period of time.
 3. The apparatus ofclaim 1 wherein said driving means drives said roller in response tosaid detection signal until a specified length of said photosensitivesheet is pulled out.
 4. The apparatus of claim 1 further comprisingmeans for separating said roller from said photosensitive sheet when apredetermined length of said photosensitive sheet has been pulled out ofsaid cartridge by said roller.
 5. The apparatus of claim 1 wherein saidcartridge contains an internal roller near said outlet, a part of saidinternal roller being exposed externally and said photosensitive sheetcontacting said externally exposed part of said internal roller.
 6. Theapparatus of claim 1 wherein said cartridge includes a flexiblepartitioning means which partitions the interior of said cartridge intoa first chamber containing unused portion of said photosensitive sheetand a second chamber for containing used portion of said photosensitivesheet, said outlet leading out of said first chamber, said cartridgefurther having an inlet into said second chamber for passing said usedportion of said photosensitive sheet inward therethrough from outside.7. The apparatus of claim 1 wherein said cartridge also has an inlet forpassing used portion of said photosensitive sheet therethrough fromoutside, said image formation apparatus further comprising a pair ofinlet rollers at said inlet for passing said photosensitive sheettherebetween into said housing, and motion communicating means forcommunicating driving power from an external power source to said inletrollers.
 8. An image formation apparatus comprisinga cartridge having anoutlet and containing a rolled photosensitive sheet, a roller disposednear said outlet for contacting said photosensitive sheet to therebypull said photosensitive sheet out of said cartridge, and means forseparating said roller from said photosensitive sheet when a predefinedlength of said photosensitive sheet has been pulled out of saidcartridge.
 9. The apparatus of claim 8 wherein said cartridge containsan internal roller near said outlet, a part of said internal rollerbeing exposed externally and said photosensitive sheet contacting saidexternally exposed part of said internal roller.
 10. The apparatus ofclaim 8 wherein said cartridge includes a flexible partitioning meanswhich partitions the interior of said cartridge into a first chambercontaining unused portion of said photosensitive sheet and a secondchamber containing used portion of said photosensitive sheet, saidoutlet leading out of said first chamber, said cartridge further havingan inlet into said second chamber for passing said used portion of saidphotosensitive sheet inward therethrough from outside.
 11. The apparatusof claim 8 wherein said cartridge also has an inlet for passing saidused portion of said photosensitive sheet therethrough from outside,said image formation apparatus further comprising a pair of inletrollers at said inlet for passing said photosensitive sheet therebetweeninto said housing, and motion communicating means for communicatingdriving power from an external power source to said inlet rollers.
 12. Acartridge containing a rolled photosensitive sheet comprisinga housinghaving an outlet for said photosensitive sheet, and a single rollerdisposed inside said housing and at said outlet, a part of said rollerbeing exposed externally and said photosensitive sheet contacting saidexternally exposed part of said roller.
 13. The cartridge of claim 12further comprising a flexible partitioning means inside said housing,said partitioning means partitioning the interior of said housing into afirst chamber containing unused portion of said photosensitive sheet anda second chamber for containing used portion of said photosensitivesheet, said outlet being formed to said first chamber and said housingfurther having an inlet into said second chamber.
 14. The cartridge ofclaim 12 wherein said housing is further formed with an inlet, saidcartridge further comprising a pair of inlet rollers disposed at saidinlet for passing used portion of said photosensitive sheet therethroughinto said housing, and power communicating means for communicatingdriving power from an external power source to said inlet rollers. 15.The cartridge of claim 13 further comprising a pair of inlet rollersdisposed at said inlet for passing used portion of said photosensitivesheet therebetween into said housing, and power communicating means forcommunicating driving power from an external power source to said inletrollers.
 16. The cartridge of claim 1 wherein said single rollersubstantially entirely covers said outlet.
 17. A cartridge containing arolled photosensitive sheet comprisinga housing, a flexible partitioningmeans inside said housing, said partitioning means partitioning theinterior of said housing into a first chamber containing unused portionof said photosensitive sheet and a second chamber for containing usedportion of said photosensitive sheet, said housing being formed with anoutlet from said first chamber for passing photosensitive sheet outwardtherethrough and an inlet into said second chamber for passing saidphotosensitive sheet inward therethrough from outside.
 18. The cartridgeof claim 17 further comprising a pair of inlet rollers disposed at saidinlet for passing used portion of said photosensitive sheet therebetweeninto said housing, and power communicating means for communicatingdriving power from an external power source to said inlet rollers.
 19. Acartridge containing a rolled photosensitive, sheet comprisinga housingformed separately with an outlet opening and an inlet opening for saidphotosensitive sheet to pass therethrough, a pair of inlet openingrollers at said inlet for passing said photosensitive sheet therebetweeninto said housing, and motion communicating means for communicatingdriving power from an external power source to said inlet rollers. 20.The cartridge of claim 19 further comprising an outlet roller which isdisposed inside said housing and substantially entirely covers saidoutlet opening, a part of said outlet roller being exposed externallyand said photosensitive sheet contacting said externally exposed part ofsaid outlet roller.